1. Field of the Invention
The present invention relates to a light shielding apparatus that may realize a transparent mode and a light-shielding mode, a method of fabricating the light shielding apparatus, and a transparent display device including the light shielding apparatus.
2. Discussion of the Related Art
Recently, with the advancement of the information age, display devices for processing and displaying a large amount of information have been promptly developed. More particularly, various flat panel display (FPD) devices have been introduced and spotlighted.
Detailed examples of the flat panel display devices include liquid crystal display (LCD) devices, plasma display panel (PDP) devices, field emission display (FED) devices, electroluminescence display (ELD) devices, and organic light emitting display (OLED) devices. The flat panel display devices generally have excellent properties of a thin profile, light weight and low power consumption and thus their application fields have been increased continuously. In particular, in most of electron devices or mobile devices, the flat panel display device has been used as a user interface.
Also, studies of transparent display devices through which a user may see objects or images located at an opposite side have been actively made. The transparent display devices may have advantages of better use of space, interior and design, and may have various application fields. The transparent display devices may solve spatial and temporal restrictions of the existing electronic devices by realizing functions of information recognition, information processing and information display as a transparent electronic device. Such transparent display devices may be used for a smart window, which may be used as a window of a smart home or a smart car.
Of the transparent display devices, the transparent display device based on LCD technology may be realized by applying an edge type backlight thereto. However, the transparent display device to which LCD technologies are applied has a problem in that transparency can be deteriorated by a polarizing plate used for realization of black. Also, a problem occurs in outdoor visibility of the transparent display device based on LCD technology.
The transparent display device based on OLED technology has power consumption higher than that of the LCD technology and has a difficulty in displaying a true black. Also, although the transparent display device based on OLED technology has no problem in a contrast ratio under a dark environment, a problem occurs in that a contrast ratio is deteriorated under a normal environment.
Therefore, to realize a transparent mode and a light shielding mode, an apparatus based on polymer dispersed liquid crystals (hereinafter, referred to as “PDLC”) may be used as a light shielding apparatus of a transparent display device based on OLED technology. The PDLC may be formed by mixing a monomer with liquid crystals, changing the monomer to a polymer through ultraviolet (hereinafter, referred to as “UV”) hardening and making the liquid crystals at a droplet state inside the polymer.
If an electric field is applied to PDLC, arrangement of the liquid crystals arranged inside the polymer is varied. Therefore, the PDLC may scatter or transmit light which is externally incident. That is, an apparatus based on the PDLC may scatter or transmit light even without a polarizing plate, the apparatus may be applied to a light shielding apparatus of a transparent display device.